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abdo28
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decoding can bus from racepack pdm

hi i need some help to decode can bus data from racepack pdm i get some info using device that monitor it

standard massage   canA    not extended (11bit)

baudrate 250kb/s

so i attached some load to the pdm and monitior the changes on the data on/off

(can address on hex)              data1              data2                     data3               data4              data5                data6             data7              data8      

                    (1b3)                 0b                   fe                           00                    00                  fe                       00                00                   00                       when          off

                                            0b                   fe                           af                     01                  fe                       85                04                   01                       when           on

on my pdm softwear i got three     parametrs   for the output (current/voltage/status)

 

 

abdo28
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hi i figure it             

hi i figure it              data 3 /4       are    16bit         is   current        start bit      24

                              data 6/7        are    16 bit        is  voltage        start  bit      48

                              data 8           are    8 bit         is  output      status   bit      56         this show      off/on/blowen fusr

but i cant figure out how to scale it the reading is difrrent from the device any help on that

 

 

AEM_SB
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Joined: 06/07/2014 - 14:29
It would be very difficult to

It would be very difficult to help reverse-engineer message data, especially via forum posts. Are you sure Racepak doesn't publish the message info somewhere? Have you tried contacting them to ask for it?

abdo28
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YES  I  tried contacting them

YES  I  tried contacting them and they say its not for public

AEM_SB
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It might be possible to find

It might be possible to find how a reading should be scaled if you have a few examples of the raw data and the matching scaled value. (Raw Data) * (Scaling Factor) = (Scaled Data),   so to find the scaling factor the math is just (Scaling Factor) = (Scaled Data) / (Raw Data).   Plug in known numbers for raw data and scaled data and it you should get a pretty good estimate for the scaling factor.

 

Hope that helps,

SB

abdo28
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hi can you have look at this

hi can you have look at this

0X0300       raw data (768)         at         0.03      volts

0Xb104       raw  data(45316)      at        11.97    volts

abdo28
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any help i scale it but when

any help i scale it but when changing device that are connected to the pdm i get difrrent reading

abdo28
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any help

any help

abdo28
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Last seen: 2 weeks 3 days ago
Joined: 11/14/2014 - 15:16
raw data 46340 at 12.05 volts

raw data 46340 at 12.05 volts        so     46340X0.26= 12.048

raw data 33028 at  11.5 volts       so      33028X0.26= 8.587

using 0.26 as scale factor give diffrent results any help

KeithStarr
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Last seen: 4 weeks 1 day ago
Joined: 08/23/2019 - 02:30
Byteswap and divide by 100

Byteswap and divide by 100

Keith Starr
keith@starr.technology
Wichita Raceway Park - 1/8 mile dragstrip and advanced drag racing test facility

KeithStarr
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Last seen: 4 weeks 1 day ago
Joined: 08/23/2019 - 02:30
 VOLTAGE       RAW       RAW 

   VOLTAGE       RAW      RAW    SWAPPED   SWAPPED   SCALED     DIFF
      0.00       768     0300     0003      0003      0.03     +0.03
     11.50     33028     8104     0481      1153     11.53     +0.03
     11.97     45316     B104     04B1      1201     12.01     +0.04
     12.05     46340     B504     04B5      1205     12.05      0.00

Keith Starr
keith@starr.technology
Wichita Raceway Park - 1/8 mile dragstrip and advanced drag racing test facility